Replaces full-file MP3 decode with a progressive WAV engine that fetches
stems in 10-second chunks and chains AudioBufferSourceNodes back-to-back.
- First audio after ~7 MB download (one chunk for 4 stems) vs. waiting
for the complete file
- Peak RAM ~28 MB vs. ~420 MB for a 5-minute 4-stem track
- No track-length cap (removes the 7-14 min OOM limit)
- Same glitch-free behavior on Safari/WKWebView: AudioBufferSourceNode,
no streaming elements, no HTTP/1.1 connection-cap underruns
- Backend needs no changes: Starlette FileResponse handles Range requests
Closes#236
Tha.Les
52197aa25c